Regularized Semi-Supervised Metric Learning with Latent Structure Preserved

Metric learning is a critical problem in classification. Most classifiers are based on a metric, the simplest one is the KNN classifier, whose outcome is directly decided by the given metric. This paper will discuss semi-supervised metric learning. Most traditional semi-supervised metric learning algorithms preserve the local structure of all the samples (including labeled and unlabeled) in the input space, when making the same labeled samples together and separating different labeled samples. In most existing methods, the local structure is calculated by the Euclidean distance which uses all the features. As we all know, high dimensional data lies on a low dimension manifold, and not all the features are discriminative. Thus, in this paper, we try to explore the latent structure of the samples and use the more discriminative features to calculate the local structure. The latent structure is learned by clustering random forest and cast into similarity between samples. Based on the hierarchical structure of the trees and the split function, the similarity is obtained from discriminant features. Experimental results on public data sets show our algorithm outperforms the traditional similar related algorithms.

Every nephron deserves a second chance before nephrectomy in obstructed uropathy due to urolithiasis

Objective: In this case report, we aimed to present our clinical experience in a patient with hydronephrotic and atrophic kidney due to impacted lower ureteral stone. Case description: A 56-year-old male was admitted to our emergency department with flank pain and nausea. A computed tomography scan revealed a 3 cm stone at the distal ureter, causing severe hydroureteronephrosis. Right kidney parenchyma was extremely thin at the medial zone, and some parenchyma was apparent at the upper and lower poles. We planned renal scintigraphy, but it was impossible to perform quickly due to the active appointment list. The patient’s kidney was assumed to be atrophic/non-functioning; however, given the long waiting list for renal scintigraphy and the patient’s intractable pain, we decided to relieve the patient’s pain with urinary drainage. Nephrostomy insertion was denied because of the extra thin parenchyma. About 40 days later, the patient underwent semi-rigid ureterorenoscopy under spinal anesthesia. It was impossible to place a double J stent to the ureter because of the kinked and extremely dilated ureter. So, we decided to place an open-end 6Fr ureter catheter. DMSA renal scintigraphy showed 33% right kidney and 67% left kidney function. Conclusion: Intractable flank pain might be a predictor of functioning renal parenchyma in hydronephrotic/atrophic kidneys. Renal split function lower than 10% on DMSA scintigraphy might not be an absolute indication of nephrectomy, especially in the obstructed renal unit. Evaluation of renal function after eliminating obstruction might be more reliable.

Social Evolution With Decoupling of Multiple Roles of Biogenic Amines Into Different Phenotypes in Hymenoptera

Convergent evolution of eusociality with the division of reproduction and its plastic transition in Hymenoptera has long attracted the attention of researchers. To explain the evolutionary scenario of the reproductive division of labor, several hypotheses had been proposed. Among these, we focus on the most basic concepts, i.e., the ovarian ground plan hypothesis (OGPH) and the split-function hypothesis (SFH). The OGPH assumes the physiological decoupling of ovarian cycles and behavior into reproductive and non-reproductive individuals, whereas the SFH assumes that the ancestral reproductive function of juvenile hormone (JH) became split into a dual function. Here, we review recent progress in the understanding of the neurohormonal regulation of reproduction and social behavior in eusocial hymenopterans, with an emphasis on biogenic amines. Biogenic amines are key substances involved in the switching of reproductive physiology and modulation of social behaviors. Dopamine has a pivotal role in the formation of reproductive skew irrespective of the social system, whereas octopamine and serotonin contribute largely to non-reproductive social behaviors. These decoupling roles of biogenic amines are seen in the life cycle of a single female in a solitary species, supporting OGPH. JH promotes reproduction with dopamine function in primitively eusocial species, whereas it regulates non-reproductive social behaviors with octopamine function in advanced eusocial species. The signal transduction networks between JH and the biogenic amines have been rewired in advanced eusocial species, which could regulate reproduction in response to various social stimuli independently of JH action.

Assessment of Renal Function Based on Dynamic Scintigraphy Parameters in the Diagnosis of Obstructive Uro/Nephropathy

This study evaluates the usefulness of parameters allowing assessment of renal function in absolute values in dynamic renal scintigraphy (DRS) with 99mTc-ethylenedicysteine (99mTc-EC) uptake constant (K), mean transit time (MTT), and parenchymal transit time (PTT) in the diagnosis of obstructive uro/nephropathy. The study included 226 people: 20 healthy volunteers, for whom normative values of assessed parameters were determined, and 206 patients. Reproducibility of results obtained by two independent operators, specificity, correlation with estimated GFR (eGFR), and Cohen’s kappa were used to evaluate reliability of assessed parameters. Normative values were as follows: K ≥ 1.6, MTT ≤ 250 s, and PTT ≤ 225 s. Reproducibility of determination of K (rs = 0.99) and MTT (rs = 0.98) was significantly higher than that of PTT (rs = 0.95) (p = 0.001). Specificity was 100% for K, 81% for MTT, and 91% for PTT. Correlation of eGFR with K (rs = 0.89) was significantly higher than with PTT (rs = 0.53) and with split function (SF) (rs = 0.66) (p < 0.0001). Cohen’s kappa was κ = 0.89 for K, κ = 0.88 for MTT, and κ = 0.77 for PTT. In a group of patients where standard DRS parameters are unreliable (bilateral obstructive uro/nephropathy or single functioning kidney), the use of K (the most effective among assessed parameters) changed the classification of 23/79 kidneys (29%). K enables reproducible assessment of absolute, individual kidney function without modifying routine DRS protocol. Diagnostic value of MTT and PTT is limited.

Critical analysis of the outcome of primary unilateral vesicoureteral reflux in a medium volume center

Background Vesicoureteral reflux (VUR) is a common finding in pediatric age group. Here in we explored the possible risk factors that affect the rate of resolution in patients with primary unilateral VUR under conservative treatment. Methods Between 2006 and 2014, we retrospectively evaluated all VUR patients and included only patients with primary unilateral VUR. Records were reviewed for patient age at diagnosis, antenatal history, patient gender, mode of presentation, side, and grade of VUR, associated hydronephrosis (HN) on renal ultrasound, presence of scarring and split function on dimercaptosuccinic acid (DMSA) scan. Clinical and radiological outcomes were assessed. Both univariate and multivariate analysis were conducted. Results A total of 68 patients with primary unilateral VUR were included (32 boys and 36 girls) with a mean age of 10 months (range 1–32). Antenatal HN was detected in 50% of patients. In 15 cases (22%), VUR was of high grade (IV–V). Associated HN was evident in 39 patients (57%). DMSA scans showed renal scarring in 16 patients (23%). After a mean follow-up of 7 years, VUR resolved in 49 patients (72%). Significant predictors for VUR resolution were VUR grade, DMSA split function and associated high-grade HN. High-grade HN with VUR was the only significant independent risk factor. Conclusions The rate of resolution in primary unilateral VUR under conservative treatment is significantly affected by VUR grade, DMSA split renal function and the presence of associated HN. Association of high-grade HN with VUR carries a low chance for spontaneous resolution.

Effectiveness of Ureteric Reimplantation on Non-Refluxing Obstructive Congenital Megaureter

Background: One in ten thousand children born with megaureter. A significant portion of this groups are of obstructed variety and the rest are refluxing ureter. It can cause obstructions and back pressure renal damage. Early diagnosis and treatment can stop deterioration of renal function and prevent complications like renal failure. Definitive treatment is uretero-neocystostomy with or without tailoring the ureter. Objective: Objective of this study was to observe the effectiveness of ureteric reimplantation on non-refluxing obstructive congenital megaureter. To achieve this objective we had observed serum creatinine level pre and postoperatively and assessed structural changes in kidney by ultrasonogram, IVU, MCU and RGP pre and postoperatively. We also observed the split renal function and split GFR of the affected kidney both pre and post operatively. Methods: This was a cross-sectional observational study. This study comprise of 35 cases of congenital non-refluxing obstructed megaureter, who were admitted in BIRDEM General Hospital and multiple other hospitals in Dhaka city from July 2013 to December 2014. Diagnosis was made by intravenous urography (IVU) reveling a dilated lower third or entire ureter with narrow tapering lower end. Obstruction was also confirmed by diuretic Tc99m DTPA scan. A voiding cystourethrogram was obtained to exclude VUR. Those with poor renal function were evaluated by ultrasonography, DTPA scan and retrograde ureteropyelography. Results: Of 35 patients, 20 were male and 15 were female. Age range 2 to 19 years. All patients underwent ureteric reimplantation, with tailoring in 15 cases. Post-operative mean serum creatinine was 0.99±0.34 which showed improvement. Split function in DTPA renogram and split GFR of patient with POM in the affected right side also showed improvement (29.49±4.02 and 29.64±4.86) as well as affected in left side (27.77±4.18 and 28.02±5.31). Conclusion: Ureteral tailoring with an extravesical ureteral reimplantation can be performed safely and effectively for primary obstructive megaureter. It is found that, ureteroneocystostomy ensured free renal drainage and preserved renal function as well as prevented complications and further deterioration. Bangladesh Journal of Urology, Vol. 21, No. 1, January 2018 p 20-24

Can parapelvic cysts lead to a non-functioning kidney?

We present a case of non-functioning kidney secondary to a parapelvic cyst in a 45-year-old male who was investigated for a single episode of self-limiting left-sided flank pain. Initial contrast-enhanced computerized tomography (CT) with delayed phases showed a 4 cm left parapelvic cyst and mild renal pelvis dilatation with no other features of obstruction. A Mercaptoacetyltriglycine (MAG3) functional scan showed 52% split function in the affected kidney and prompt drainage with no evidence of obstruction. Although completely asymptomatic after the initial episode we opted to follow him up. Eighteen months on we discovered an atrophic kidney on repeat imaging with a split function of 9% with no change in parapelvic cyst size. We propose that an intermittent silent obstruction, caused by infundibular compression deep inside the kidney, may have caused calyceal dilatation and eventual loss of function in this case. We discuss this rare presentation, review the literature and propose a follow up plan. Level of evidence: Level 5

Comparison of glomerular filtration rate (GFR) with Tc-99m-DTPA and tubular extraction rate (TER) with Tc-99m-MAG3 in potential living kidney donors: Feasibility of a one-day protocol

Aim Sufficient glomerular filtration rate (GFR) is mandatory in living kidney donors (LKD) before renal transplantation (RT). Guidelines recommend exogenous GFR (e. g. Tc-99m-DTPA) besides estimated GFR by plasma creatinine (eGFR). Tc-99m-MAG3 determines split function and tubular extraction rate (TER). This study evaluated a time-efficient one-day protocol for DTPA and MAG3 in potential LKD. Methods Retrospective analysis of 82 consecutive potential LKD (female, 52; age, 54 [19–73] a). DTPA GFR (Fleming formula) with blood sampling 169 (147–205) min post injection of 27 (18–59) MBq Tc-99m-DTPA. 199 (181–219) min after DTPA injection, same-day renal scintigraphy with 105 (65–150) MBq MAG3 followed (TER according to Bubeck). Sufficient GFR for RT was defined age- and sex-dependent based on British guidelines, normal TER at 70 % of age-dependent average. In 15 separate potential LKD, a blank blood sample before MAG3 injection allowed estimation of remaining DTPA counts and resulting TER error. Results Remaining Tc-99m-DTPA blood counts during sampling for MAG3 led to median TER underestimation by 12 (IQR, 8–15) ml/min/1.73 m2. Before blood count correction, 16/82 patients had reduced TER despite sufficient GFRFleming in 13/16 patients. After correction, TER remained reduced in 9/82 patients who all had sufficient GFRFleming. 10/82 patients had insufficient eGFR (CKD-EPI) but sufficient GFRFleming. Correlation coefficient for TER and GFRFleming was ρ = 0.76, for eGFR and GFRFleming ρ = 0.61, and for TER and eGFR ρ = 0.55. Conclusion A one-day protocol for Tc-99m-DTPA GFR and MAG3 dynamic imaging is feasible. If TER is calculated, the proposed method for blood count correction may be applied. However, relevance of the TER remains questionable due to frequent discordance to GFR.